Biology Reference
In-Depth Information
3
Floods, Temperature, Evolution,
and It's about Time
GLOBAL SEA LEVELS
One of the valuable contexts within which paleobiological infor-
mation can be assessed and interpreted is the history of the Earth's
sea levels. When they are high, continental margins and low-lying
interiors are fl ooded, making for more extensive maritime climates
that buffer the land from temperature extremes. High waters may
disrupt or limit the extent of land bridges such as those across
Beringia, the North Atlantic Ocean, Panama, and the Scotia Sea
between Antarctica and South America. When the extent of land
surface changes, albedo (refl ectivity) is affected because water ab-
sorbs and releases heat more slowly than land. If sea levels were
higher than at present by 100-300 m, as they were during the Cre-
taceous, this factor, if acting alone, would change the albedo index
by about 0.03 and result in a temperature rise of around 3°C.
Another consequence of sea level change, together with orog-
eny, is the effect it has on atmospheric chemistry (e.g., CO 2 con-
Search WWH ::




Custom Search